The ESR test measures the erythrocyte
sedimentation rate, which is how quickly red blood cells settle at the bottom
of a blood sample. Doctors cannot use the results of the test to diagnose a
specific disease because many different health conditions can cause the ESR to
be high or low.
Doctors call the ESR test a nonspecific test,
as it only confirms the presence or absence of inflammatory activity in the
body. Doctors typically use other lab tests, clinical findings, and the
person's health history alongside ESR test results to make a diagnosis.
Inflammation usually
occurs in the body as a result of underlying medical conditions, such as infection, cancer, or an autoimmune disease.
Doctors
also use the ESR test to monitor how conditions, such as those below, are
progressing or responding to treatment.
·
rheumatoid arthritis, an
autoimmune condition that causes inflammation in the joints
·
temporal arteritis, a type of blood
vessel inflammation
·
polymyalgia
rheumatica, a complication of temporal arteritis
·
systemic
vasculitis, inflammation of the lining of the blood vessels
In
this article, we look at the ESR test procedure and what the results might
indicate. We also explain the possible risks of the procedure.
Procedure
The ESR test measures the rate at which the
red blood cells, or erythrocytes, in a sample of blood settle at the bottom.
This process of settling is called sedimentation.
A
doctor will draw a small amount of blood from the individual's vein and send it
to a laboratory. There, lab technicians will transfer the blood to a vertical
test tube in which the red blood cells will slowly settle at the bottom. This
will leave a clear, yellowish fluid at the top, which is blood plasma.
The
result of the test will depend on the amount of plasma at the top of the tube
after 1 hour. The measurement will be in millimeters per hour (mm/hr).
Red
blood cells settle at a faster rate in people with inflammatory conditions.
These conditions trigger an inflammatory process in the body, which leads to an
increase in the number of proteins in the blood. This increase causes red blood
cells to clump together and settle more quickly.
People
whose red blood cells settle faster will have elevated ESR values, indicating
to doctors that a medical condition may be present.
Results
The
result of the ESR test is the amount of plasma remaining at the top of the test
tube after 1 hour.
The
test is not specific to a particular condition, which means that doctors have
to use the results alongside other clinical information to make an accurate
diagnosis and determine whether or not the individual has a disease.
The normal reference range for
ESR results is 1–13 mm/hr for males and 1–20 mm/hr for females. These values
can also vary depending on the person's age. People with ESR results outside
the standard range may have a medical condition.
Low
levels
People
with low ESR values may have:
·
sickle cell anemia,
a condition that affects the shape of red blood cells
·
leukemia,
a blood cell cancer
·
a high red blood
cell count
·
congestive heart failure
·
low levels of
the protein fibrinogen in the blood
·
hyperviscosity,
an increase in blood thickness
·
a very high white
blood cell count
Moderately
elevated results
A moderately elevated ESR may not always
indicate a health condition.
However,
it is possible that people whose ESR value is slightly high may have one of the
following conditions:
·
rheumatoid
arthritis
·
anemia, a
reduced number of red blood cells
·
thyroid disease
·
kidney disease
·
red blood cell
abnormalities, such as macrocytosis
·
some forms of
cancer, such as lymphoma
·
tuberculosis,
a type of lung infection
·
a bone infection
·
a heart
infection
·
a systemic
infection
Extremely
elevated results
An
extremely high ESR value, which is one above 100 mm/hr, may indicate one of
these conditions:
·
multiple myeloma,
a cancer of plasma cells
·
Waldenstrom's
macroglobulinemia, a white blood cell cancer
·
temporal
arteritis or polymyalgia rheumatica
·
hypersensitivity
vasculitis, a reaction to an allergen that results in blood vessel inflammation
Doctors
will typically compare the ESR test result with other test results to confirm a
suspected diagnosis. They will also consider the symptoms and signs that a
person is experiencing and their personal and family medical history.
No comments:
Post a Comment